Over-expression of aspartate aminotransferase genes in rice resulted in altered nitrogen metabolism and increased amino acid content in seeds |
| |
Authors: | Ying Zhou Hongmei Cai Jinghua Xiao Xianghua Li Qifa Zhang Xingming Lian |
| |
Institution: | (1) National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070 Wuhan, China |
| |
Abstract: | Aspartate aminotransferase (AAT) is a key enzyme in the synthesis of amino acids. It plays an important role in regulating
carbon and nitrogen metabolism in almost all organisms. In this study, we over-expressed in rice separately all three AAT genes from rice (OsAAT1~3) and one AAT gene from Escherichia coli (EcAAT). Over-expression was driven by the CaMV 35S promoter and constructs were introduced into rice by Agrobacterium tumefaciens-mediated transformation. Compared with control plants, the transformants showed significantly increased leaf AAT activity
and greater seed amino acid and protein contents. No other phenotypic changes were observed. The total leaf AAT activities
in plants over-expressing OsAAT1, OsAAT2, and EcAAT were 26.6, 23.6, and 19.6 A min−1 mg−1 FW (A: units of activity, defined as increase of absorbency per min per mg; FW: fresh weight), which were significantly higher
than that in the wild-type control (17.7 A min−1 mg−1 FW). The amino acid content in seeds of transgenic plants over-expressing OsAAT1, OsAAT2, and EcAAT was 119.36, 115.36, and 113.72 mg g−1, respectively, which were 16.1, 12.0, and 5.4% higher, respectively, than that in the control plants. The transgenic plants
over-expressing OsAAT1, OsAAT2, and EcAAT had significantly higher protein contents (increased 22.2, 21.1, and 11.1%, respectively) than wild-type plants. No significant
changes were found in leaf AAT activity, seed amino acid content or protein content in OsAAT3 over-expressed plants. The expression patterns of the three OsAAT genes and their different functions are also discussed. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|